基于格子Boltzmann方法的液润表面减阻规律

The drag reduction mechanism of liquid-infused surface based on lattice boltzmann method

[目的]近年来,液润表面(LIS)作为一种新型的减阻表面被提出。它将传统疏水表面微沟槽中残存的气体替换为润滑油,进而提高了减阻效果的稳定性。为了更全面地认识液润表面,研究润滑油溶解性对滑移长度的影响。[方法]基于格子Boltzmann方法(LBM)伪势模型,对液润表面的滑移现象进行数值模拟,研究润滑油溶解密度和外部剪切率对滑移长度的影响规律。[结果]液润表面可以产生滑移现象,当润滑油完全混溶或极难溶时,滑移长度与组分间分子作用强度有较好的线性关系。[结论]润滑油难溶于水时,组分间作用力越大,减阻效果越好。且滑移长度不显著依赖于剪切率,润滑油的减阻特性与传统超疏水壁面的减阻特性有相似性。

[Objectives]Newly proposed in recent years,the liquid-infused surface(LIS)is a drag reduction surface which replaces the residual air conserved by the microgrooves of a traditional superhydrophobic sur-face with a lubricant,thereby vastly improving the stability of the drag reduction level.To fully understand the drag reduction stability of LIS,this paper focuses on the influence of lubricant solubility on drag reduction.[Methods]Based on the lattice Boltzmann method(LBM),we simulated a conserving lubricant microstruc-ture with microflow and studied the influence of the lubricant's dissolved density and shear velocity on slip length.[Results]The liquid-infused surface results in a slip phenomenon,and there exists a linear relation-ship between slip length and cohesion force strength among its particles when the lubricant is completely dis-solved or difficult to dissolve.[Conclusions]With greater cohesion force strength among its particles,a lubricant can result in more promising drag reduction when it is difficult to dissolve.The lubricant's shear ve-locity has little influence on slip length.The properties of the lubricant are similar to those of a traditional su-perhydrophobic surface.